Failure phenomenon: a 2008 annual output of FAW – Volkswagen Magotan 2.0TSI car, mileage 42000 km. According to reflect the user, the light warning light on the instrument may vehicle lighting (FIG. 1).
FIG 1
Check Analysis: First, verification failure phenomenon. As the user, after starting the engine about 3 min, the fault light on the instrument will flash several times after the warning light is not lit put on, check all normal lighting headlight, the headlight does not affect the function. Starting about 3 engine, this failure phenomenon will occur one time.
Use VAS5052A fault diagnostic detection, the system stores a plurality of related DTCs left headlamp, respectively 02233 (left headlamp module J667 no signal power / communication), 01042 (control unit uncoded ), 02656 (left headlamp uncoded power module J667), and 01539 (headlight is not adjusted basic setting / no match or incorrect), the fault code can not be cleared. Further testing found encoding a left headlamp power module does not correct and should be 35 encoding. After encoding, the fault information becomes sporadic, can be cleared.
FIG. 2
J667 fault it just left headlamp coding error due to the power module it? From these fault codes stored point of view, maintenance personnel have some doubts. In order to determine the fault, it has been ruled out, maintenance personnel and related circuits are basic checks. Referring left headlamp control circuit diagram (FIG. 2), detected by the load supply line left headlamp, SC5, the fuse is normal load is 12 V power supply, the left headlamp T14d / 5, T14d / 7 and T14d / 14 and a ground line normal no virtual access phenomenon. Switch turns on the headlights, vehicle power measurement control unit J519 output pin of T11a / 4, T11a / 6 and T11a / 7 normal power supply voltage is 12 V, respectively, the left side of the gas discharge lamp drive control unit J343, near the left side light blocking V294 plate and a left parking light bulb M1. After repeated examination, headlamp system (address code 55) no fault code appears, the power supply module tests the left headlamp waveform positive CAN-HChang (FIG. 3).
Figure 3
is repeated a plurality of times to start the engine and turn the headlamp switch, and finally found that the output power is left headlamp CAN-H and CAN-L there is an abnormality (FIG. 4) waveform, the fault information before the system again, whereby the power can be concluded that the left headlight module J667 of sporadic data transmission fails, the lighting failure causes sporadic fault warning light on the instrument .
Figure 4
Solution: Replace the left headlamp assembly includes a left headlamp J667 including the power module, follow-up visits to confirm the failure did not recur .
(Ma Ji)